A city is like a living body. If viewed from the sky, the crisscross roads are like arteries dividing the city into a number of small zones, with small alleys zigzagging through building blocks. The alleys dotting the whole city are like blood capillaries that are tiny but full of life. The names of these small alleys vary from one place to another, one time period to another and one ethnic group to another. They are called "longtang" in Shanghai.

Some say longtangs are the background of Shanghai City. It is absolutely true. Longtangs of varied widths and sizes have witnessed the ups and downs of the city, just like hutongs in Beijing that have played the same role. Shanghai is developing as time goes by, Shikumen buildings (stone gate houses) inside longtangs also keep developing in a silent way. When the sunlight is blotted out by things nearby, the longtangs are still standing where they are, quietly watching the stories about to unfold in the city.

Life in the narrow space has been continuing for over 100 years since the first generation entered the longtangs in Shanghai. Today, some people have moved out of longtangs and into new high-rise buildings and some are planning to follow suit, with the rest still living in longtangs. For those left, longtangs are in memory; and for those remained, longtangs are in real life.